22 lines
649 B
TypeScript
22 lines
649 B
TypeScript
export const colorIsDark = color => {
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if (typeof color === 'undefined') {
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return true // Defaults to dark
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}
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if (color === '#' || color === '') {
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return true // Defaults to dark
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}
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if (color.substring(0, 1) !== '#') {
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color = '#' + color
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}
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const rgb = parseInt(color.substring(1, 7), 16) // convert rrggbb to decimal
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const r = (rgb >> 16) & 0xff // extract red
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const g = (rgb >> 8) & 0xff // extract green
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const b = (rgb >> 0) & 0xff // extract blue
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// luma will be a value 0..255 where 0 indicates the darkest, and 255 the brightest
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const luma = 0.2126 * r + 0.7152 * g + 0.0722 * b // per ITU-R BT.709
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return luma > 128
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} |